On 03/03/2020 11:51 am, Marc Zyngier wrote:
The way cookie_init_hw_msi_region() allocates the iommu_dma_msi_page
structures doesn't match the way iommu_put_dma_cookie() frees them.
The former performs a single allocation of all the required structures,
while the latter tries to free them one at a time. It doesn't quite
work for the main use case (the GICv3 ITS where the range is 64kB)
when the base ganule size is 4kB.
This leads to a nice slab corruption on teardown, which is easily
observable by simply creating a VF on a SRIOV-capable device, and
tearing it down immediately (no need to even make use of it).
Fix it by allocating iommu_dma_msi_page structures one at a time.
Bleh, you know you're supposed to be using 64K pages on those things,
right? :P
Fixes: 7c1b058c8b5a3 ("iommu/dma: Handle IOMMU API reserved regions")
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Robin Murphy <robin.murphy@xxxxxxx>
Cc: Joerg Roedel <jroedel@xxxxxxx>
Cc: Eric Auger <eric.auger@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
drivers/iommu/dma-iommu.c | 36 ++++++++++++++++++++++++------------
1 file changed, 24 insertions(+), 12 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index a2e96a5fd9a7..01fa64856c12 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -171,25 +171,37 @@ static int cookie_init_hw_msi_region(struct iommu_dma_cookie *cookie,
phys_addr_t start, phys_addr_t end)
{
struct iova_domain *iovad = &cookie->iovad;
- struct iommu_dma_msi_page *msi_page;
- int i, num_pages;
+ struct iommu_dma_msi_page *msi_page, *tmp;
+ int i, num_pages, ret = 0;
+ phys_addr_t base;
- start -= iova_offset(iovad, start);
+ base = start -= iova_offset(iovad, start);
num_pages = iova_align(iovad, end - start) >> iova_shift(iovad);
- msi_page = kcalloc(num_pages, sizeof(*msi_page), GFP_KERNEL);
- if (!msi_page)
- return -ENOMEM;
-
for (i = 0; i < num_pages; i++) {
- msi_page[i].phys = start;
- msi_page[i].iova = start;
- INIT_LIST_HEAD(&msi_page[i].list);
- list_add(&msi_page[i].list, &cookie->msi_page_list);
+ msi_page = kmalloc(sizeof(*msi_page), GFP_KERNEL);
+ if (!msi_page) {
+ ret = -ENOMEM;
I think we can just return here and skip the cleanup below - by the time
we get here the cookie itself has already been allocated and
initialised, so even if iommu_dma_init_domain() fails someone else has
already accepted the responsibility of calling iommu_put_dma_cookie() at
some point later, which will clean up properly.
Cheers,
Robin.
+ break;
+ }
+ msi_page->phys = start;
+ msi_page->iova = start;
+ INIT_LIST_HEAD(&msi_page->list);
+ list_add(&msi_page->list, &cookie->msi_page_list);
start += iovad->granule;
}
- return 0;
+ if (ret) {
+ list_for_each_entry_safe(msi_page, tmp,
+ &cookie->msi_page_list, list) {
+ if (msi_page->phys >= base && msi_page->phys < start) {
+ list_del(&msi_page->list);
+ kfree(msi_page);
+ }
+ }
+ }
+
+ return ret;
}
static int iova_reserve_pci_windows(struct pci_dev *dev,
